Getting into the BB Ab drill, the first exercise is Ab Crunch for 30 seconds. Lie on the mat knees bent, hands crossed over the chest. Eyes to the ceiling chin off the chest. Slowly raise yourself so that the shoulders come off the mat, using your abdominal muscle pressing your lower back into the floor. Contract and slowly go back to the starting position. As you contract, exhale. The movement has to be very slow and controlled. What we just did is an Ab Crunch with hands across the chest. Conventionally what people tend do is put their hands behind their head and if done incorrectly can cause injury to your neck. .